Vibrations of a vehicle include a twist vibration that is a vibration caused by twisting such as of a crank shaft, a drive shaft, or the like of an engine, a pitching vibration that is a vibration of the vehicle in the pitching direction caused by a driving force or a braking force, and vibration of the engine.
JP-B-4483985 describes vibration damping control, focusing on making use of drive torque of an engine-driven generator, as an engine load for vibration damping. Under the control, the generation amount of the generator is varied such that the drive torque of the generator can suppress the vibration. According to this, the vibration of the vehicle can be suppressed by the drive torque of the generator.
In a vehicle as represented by a passenger car, it is well known that variations in the torque applied to a wheel shaft (wheel-shaft torque) causes unnecessary vibrations in various parts of the vehicle body. Specifically, the unnecessary vibrations include a vibration of the vehicle body (1 to 5 Hz), an engine-mounting system vibration (7 to 15 Hz), and a vibration of the chassis or the tires (not less than 10 Hz). These vibrations not only impair the car's ride but also become the factors of varying wheel's ground weight. Therefore, these vibrations may lead to lowering of the motion performance.
In contrast, in a known apparatus (e.g., see JP-A-2009-165230), an in-vehicle generator (e.g. alternator) that is driven by an engine is used as a vibration-damping actuator. Use of the generator in this way can vary the generation amount such that the drive torque of the generator can suppress the vibrations mentioned above, thereby correcting output-shaft torque of the engine, or further correcting wheel-shaft torque.